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(No ModeL) D. P. SWEET.

SELF WINDING ELEOTRIG CLOCK. No. 337,797. Patented Mar. 9, 1886'.

(fi th (rt Inventor UNITED STATES PATENT OFFICE.

=D. FRED SIVEET, OF GRAND RAPIDS, MICHIGAN, ASSIGNOR, BY DIRECT AND MESNE ASSIGNMENTS, TO THE ELECTRIC TIME COMPANY, OF SAME PLACE.

SELF-WINDING ELECTRIC CLOCK.

SPECIFICATION forming part of Letters Patent No. 337,797, dated March 9, 1886.

Applicalion filed February 23, 1894. Serial No. 121,790. (No model.)

To aZZ whom it may concern.-

Be it known that I, D. FEED SWEET, of Grand Rapids, in the county of Kent and State of Michigan, have invented new and useful Improvements in Electric Clocks; and I do hereby declare that the following is a full, clear, and exact description thereof, reference being had to the accompanying drawings, which form a part of this specification.

This invention relates to new and useful improvements in electric clocks; and the invention consists in the combination of an electric actuation, which constitutes the direct prime motor of the clock, with the ordinary going-train, the spring of which is normally kept wound, and shall be adapted to keep the clock going, if necessary, for any interval of time, say, several hours, whenever the electric motor fails to act from one cause or another. The devices are also so constructed that the prime motor will act as an automatic winding mechanism for the reserve motor.

Heretofore springs have been variously used in combination with an electric actuation; but the office of such springs was confined to keep the clock going for short intervals-such as the intervals in the pulsations of the armature; but the object of my invention is to provide the clock with a reserve motorin the form of the ordinary clock-spring, which is not only able to keep the clock going if the electric current simply misses to make contact, but keeps it going for several hours if necessary, so as to allow the replacing or refilling of the bat- B is D is the leaf-spring. G'is the barrel. E is the coil-spring of the barrel. F is the staff of the minutehand, to which the inner end of the coil-spring E is attached. H is a ratchet-disk secured to the going barrel, and I is a click engaging with the ratchet-disk. J is the staff of the second-hand, K is a crank secured to this staff. L is a contact-spring, and M is a stationary adjustable contact. P is the bat tery. R and S are the battery-wires; and T and U are insulated plates, to which the binding-posts N and O are secured.

In practice the clock-train receives the impulse from the leaf-spring D, the tension of which is made active from minute to minute by the operation of the armature. The crank K on the second-hand staff lifts the spring L into contact with the set'screw M once every minute. This closes the battery-circuit and actuates the armature B and the impulsepawl. Now, if the ratchet-disk H is provided with sixty teeth, the impulse-pawl would be able to make a new engagement at every vibration of the armature, and the minute-hand staff E would regularly move the clock-train.

Instead of providing the ratchet-disk H with sixty teeth, I provide it with less, say fifty, and for this object: Suppose the crank K should repeatedly fail to effect the proper closing of the battery-circuit, owing to some dust between the contacts or other causes, the impulse-pawl would cease to move the clocktrain. True enough there is the spring of the barrel, which would keep up the motion of the clock, but although the electric actuation may be restored again and again, the spring E finally runs down, and then at the first failure of the circuit-closer the clock would stop. This would occur with sixty teeth on the ratchet-wheel, but with less than sixty, say fifty, if the current has failed for some time to act, or is irregular in its action, it will be able to regain what it has lost, as the armature is capable to turn the ratchet-wheel one-sixth faster than is necessary. Thus if the coilspring E has been unwinding during an interval of inactivity of the current, the latter will, upon becoming active and regular again, soon wind up the spring E and keep it wound up as long as its action is normal.

By making the spring E of proper tension and long enough to run the clock for several hours it is clear that many accidental and incidental stoppages of electric clocks are avoided.

For the proper operation of the device it is necessary that the tension of the coil-spring E be normally less than the tension of the spring D, as the latter is designed to furnish the positive force to wind the mainspring E, and when the tension of the said spring E equals, or nearly so, the tension of the spring D, as when it is nearly or quite wound up, the spring D remains inoperative, thereby preventing the overwinding or straining of any of the parts.

What I claim as my invention is 1. The combination, with the minute-arbor of a clock-train, of a ratchet-wheel having a less number of teeth than the times the minute-arbor moves in one revolution and connected thereto by a spring, and an electromotive device and connections for imparting motion to the said ratchet-wheel, substantially as described. I

2. The combination, with the minute-arbor of a clock and an actuating-clock-spring fixedly secured to said minute-arbor, of a ratchetwheel independently journaled on the axis of the minute-arbor and fixedly connected to the clock-spring, aspring-operated winding-pawl, and an electric device for actuating the same, substantially as described, whereby the clockspring is wound up faster than it pays ofi' and is prevented from overwinding,

3. The combination, with the mainspring of a clock-movement, of a supplemetary spring constructed and arranged to be moved 4. In combination with the ratchet-wheel H, arbor F, and mainspring E, connecting the two and imparting a motion to the latter, a pawl, 0, connecting with the armature of an electro-magnet, A, and a spring, D, arranged to actuate the pawl at intervals through the medium of the said electro-magnet A to rotate the ratchet-wheel H proportionately faster than the arbor F and in an opposite direction to the rotation thereof, substantially as and for the purpose set forth. 7

V D. FRED SWEET." Witnesses:

E. F. SWEET, W. J. STUART. 

